Development and integrality of the regeneration leg in Eupolyphaga sinensis.

Many arthropods are able to regenerate lost body parts after injury. Here, regeneration was studied in nymphs of Eupolyphaga sinensis (Walker) (Blattaria Polyphagidae) after amputating femur, tibia or tarsus of one hind leg. The development and integrality of regeneration leg was observed and the regeneration process was studied. The results showed that new leg formed inside the end of the stump. Development of the regeneration leg in the stump experienced four stages. At first epidermal cells of the stump edge formed scab and covered the wound. Then the underlying tissue became disorganized. Blastema grew rapidly and progressively differentiated from its proximal region to undergo morphogenesis, leading to the perfect replacement of the missing structures. Finally the regeneration leg developed well and detached to the old cuticle. Cell layers of blastema of the regeneration leg were epithelium, neurofibril, regeneration cells and tracheas. Only four segments were observed in the tarsus of new leg until adult stage when amputating the base of tarsus I. Tarsus II was the key position for the integrality of the regeneration leg when amputating different tarsus position. The regeneration cells were inside the end of the stump and at the beginning of the amputated segments.